Immunohistological reactivity pattern of the anti-cutaneous T-cell lymphoma antibody BE2

SUMMARY It has been reported that the monoclonal antibody BE2, raised against leukaemic T cells, reacts specifically with malignant lymphoid cells and represents a valuable reagent for the early identification of cutaneous T‐cell lymphomas. To test this hypothesis, a comprehensive range of nodal and cutaneous biopsies have been examined immunohistologically using single and double immunoenzymatic and immunofluorescent staining methods. BE2 showed a broad range of reactivity, consistently labelling normal endothelial cells, B‐lymphocytes in mantle and marginal zones, T‐lymphocytes in the paracortex of lymph nodes and medulla of thymus, as well as a variety of different macrophage types, including Langerhans cells and dermal macrophages. Furthermore, although BE2‐positive T‐lymphocytes were most frequent in malignant lymphomas, they were also found in four of 19 benign dermatoses. We conclude that BH2 is neither T‐cell nor tumour‐cell specific, and that use of this reagent on tissue sections is unlikely to improve the diagnosis of cutaneous lymphomas.